Establishing an optimal trajectory for calcaneotibial K-wire fixation in emergent treatment of unstable ankle fractures

Abstract

OBJECTIVE: In unstable ankle fractures the associated soft tissue damage can be a therapeutic challenge. The aim of this study was to optimize planning of minimally invasive stabilization of ankle fractures by calcaneotibial transfixation, which is a demanding technique due to the complex hind foot anatomy. METHODS: In a retrospective radiographic analysis the angles and dimensions of a safe drill tunnel for calcaneotibial K-wire insertion were defined on standard radiographs of the ankle joint. 165 lateral weight-bearing radiographs (77 right; 88 left) and 147 (80 right; 67 left) mortise views of 186 (90 right; 96 left) uninjured feet from 123 patients (74 women (114 feet); 49 men (72 feet)) were included in this study. The average patient age was 49 (range, 13-85) years. Inter-and intra-observer reliability was evaluated on 20 randomized radiographs that were analyzed in a default set, three times, by two different examiners on three different days. RESULTS: In the lateral view the drilling tunnel was orientated at 59.4 • to the plantar plane with a maximum proximal variance of 7.1 image-mm. Distal variance cannot be tolerated since an ankle joint injury would ensue. In the mortise view the drill tunnel was directed with a mean angle of 18.4 • to the distal tibial articular surface. At most a mean of 11 • fibular-and 13.4 • tibial-expansion can be tolerated. Intra-and inter-observer reliability was higher for the angles than for the drill corridors. CONCLUSION: The three-dimensional (3D) orientation for safe K-wire placement for calcaneotibial transfixation should adhere to the drill tunnels established in this study.

Cadaveric Study on Retrograde Calcaneotibial Fixation of Unstable Ankle Fractures

“…All freehand-placed wires were correctly positioned within the corridor described by Schröder et al (18). Using the device, the mean intra-tibial and intra-calcaneal distances of the wires were 45.3 mm (range=26.2 to 58.2 mm) and 39.7 mm (range=30.0-58.9 mm), respectively.…”

“…The target accuracy of the experienced surgeon was shown to be superior to the target device used without any training. The development of the target device was based on previously determined angles calculated on weight-bearing radiographs of healthy feet (18). On weight-bearing radiographs, especially in hypermobile patients, who tend towards flatfoot deformity, the hindfoot axis tends towards a valgus deformity.…”

“…A more medial entry of the wire would have led to a more central position in calcaneus (dotted line). Green lines: the mediolateral dimension of the corridor for the K-wire (18). held in 30˚ of internal rotation.…”

“…Subsequently, the image intensifier images and the Iso-C 3D images were analyzed using OsiriX imaging software (OsiriX, version 3.8.1) in the sagittal plane, coronal plane and in the plane of the wire. The following measurements in the sagittal plane (lateral view) were recorded: the length of the wire in the calcaneus in the plane of the wire as well as measurement of the maximum distance to the posterior calcaneal border rectangular to the wire, the length of the wire in the tibia and the distance between the border of the distal tibia joint surface and the tibial entry point and whether the wire was located within the corridor defined by Schröder et al (18) (Figure 4). In the coronal plane (anteroposterior view), the following parameters were assessed: the width of the distal tibial articulation, the distance between the lateral tibial border and the wire entry point.…”

“…Extra-articular calcaneotibial K-wire-fixation represents a worthy alternative, but it is technically demanding (3,17). In a preliminary study, the current authors measured the ideal wire position, dimension of bony corridor as well as the optimal entry point and angle of the wire using standard radiographs (Figure 1) (18). The bony corridor keeps the risk of iatrogenic injuries very low.…”